Potential of Portuguese propolis as source of biofungicides

Abstract

Agriculture provides livelihoods for 40% of worldwide population1 . Due to the rapid human population growth, it is estimated that global food production will need to increase by 60% to feed over 9.8 billion people by 20502 . The use of pesticides contributes to high crop yields and effective farm management3 . Globally, 4.6 million tons of chemical pesticides are sprayed into the environment every year4,5. Out of the total consumption of pesticides, 17.5% are in the form of fungicides5 . Although efficient, these chemical controls have undesirable characteristics, such as the development of pathogen resistance, environmental pollution, long degradation periods, bioaccumulation in the food chain and toxicity to non-target organisms6 . Therefore, alternative paths to the intensive use of crop protection chemicals are needed, such as the use of natural products which are effective, biodegradable and leave no harmful residues. Propolis is a natural resinous mixture made by honeybees (particularly Apis mellifera L.) from various plant sources and bee wax. Hundreds of different compounds have been identified so far in propolis, including several bioactive compounds such as flavonoids and phenolic acids and terpene derivatives, generally associated to its antibacterial, antifungal, antiviral and antioxidant activities, among others7 . Previous work showed that propolis ethanol extracts (EEs) can be explored as source of biofungicides for application in a sustainable agriculture management 8. In this study we evaluated the antifungal activity of EEs from Portuguese propolis samples against a range of phytopathogenic fungal species that affect economically important crops in Portugal. Interestingly, results showed that different propolis samples have distinct fungitoxic activities but also that different fungi species exhibit distinct susceptibilities